Ladder hoist



Patented Oct. 22, 1940 UNITED STATES PATENT OFFICE LADDER HOISTApplication September 16, 1938, Serial No. 230,276

Claims.

Our invention relates generally to hoists and particularly to a hoistwhich may be remova-bly mounted on a truck or other vehicle for use byfire departments, street decorators, power and traction companies, andthe like where a portable telescopic ladder is needed.

It is the major object of our invention to provide a hoist which isparticularly suitable for the above uses, and which is also adaptable toother uses, such for example as operating the bed of a dump truck, orthe like, and which can be easily installed on any suitable vehicle andjust as easily removed when necessary.

It is a further object of our invention to provide a hoist which iseasily accessible, and because of its simplicity and durability willgive long and satisfactory service.

These and other objects and advantages of our invention will becomeapparent from the following description of a preferred embodimentthereof as a ladder hoist, and from an inspection of the accompanyingdrawings, in which:

Fig. 1 is a side elevation of a conventional fire truck equipped withour invention,

Fig. 2 is a side elevation of the ladder hoist in retracted or normalposition,

Fig. 3 is a plan view of the hoist in normal position, v

Fig. 4 is an elevational section taken on the line 4-4 in Fig. 3, v

Fig. 5 is an elevational section taken on the line 55 of Fig. 3,

Fig. 6 is a partial elevation showing the hoist in raised position,

Fig. 7 is a partial elevational section taken at in Fig. 3, and

Fig. 8 is a fragmentary vertical section taken at 88 in Fig. 3.

Referring now to the drawings, and particularly to Figs. 1-3 thereof,the numeral l0 indicates generally a suitable vehicle which in thedrawings has been illustrated as a fire truck, and the numeral I lindicates generally the ladder hoist of our invention, mounted on therear end of the truck ID by a suitable framework such as the posts l2and diagonal braces l3. As seen best in Figs. 2 and 4, the hoist ismounted on a relatively fiat table M which, in the preferred form of ourinvention, is rotatably mounted upon a base plate supported by a boxframe 16 made of horizontal channels.

The box frame I6 is provided with a pair of parallel channels I l andIla adjacent its center section, across the bottom of which a plate i8is bolted. A relatively large gear wheel l9, pro- (Cl.v 228-12) videdwith a hub 23 and spokes 2|, is secured to the upper faces of thechannels I'i and Na so that its hub is substantially co-axial with thecenter of frame I6 and table It as seen best in Fig. 4. The base plate15 is provided with a central aperture which is preferably circular inshape and of somewhat greater diameter than the gear wheel 19. The table[4 is provided with a centrally-disposed relatively small aperture, overT which is bolted an apertured bearing plate 22. A vertical shaft 23 issecured in the hub of gear IS with .its lower end passing through anaperture in plate l8 and secured thereto as by nut 24. The upper end ofthe shaft passes up through the aperture in base plate 15 and through asmall aperture in table l4 and an apertured bearing plate or boss 22, sothat the table may be rotated about shaft 23. The table is preventedfrom moving vertically by any suitable means such as the nut 25 on thetop of shaft 23.

A pair of parallel channel irons 26 and 21 are securely fastened to theupper'face of table l4, and are spaced apart a distance substantiallyequal to the width of the ladder which the hoist is to carry. A gear box23 provided with a boss 29 on its inside wall is preferably mountedadjacent one edge of the table 54, and houses beveled gears 30 and 3|carried by shafts 32 and 33, respectively. Shaft 32 is verticallydisposed within the gear box 28, extends upwardly through the topthereof, and has a handwheel 34 secured to its upper end. Shaft 33extends horizontally through the boss 29 and a bearing aperture inchannel 26 and carries a beveled gear 35 on its inner end which mesheswith a gear 36 carried on the upper end of a vertical shaft 31 rotatablymounted in table 14 and extending down through the enlarged aperture inplate l5. A gear 38 is fast to the lower end of shaft-31, and is adaptedto mesh with gear Wheel I9. By this arrangement, table 14 may be readilyrotated in a horizontal plane about the base plate [5 by simply turningthe handwheel 34 whose motion is transmitted through shaft 32, gears 30and 3!, shaft 33, gears 35 and 36, shaft 31, and gears 38 and 59 to gear38 to cause it to travel around gear H3.

The table M carries suitable ladder supporting means pivotally mountedthereon such for example as the pair of parallel legs 4! and 42 whichare adapted to have a ladder 40 securely attached thereto in such mannerthat the legs 4| and 42 act as lower extensions of the ladder legs, andare pivotally mounted on the anchor bars 23 and 2'! adjacent one endthereof by means of upstanding ears 43 and 44 through which an axial rod45 extends, the rod 45 being secured in place by means nuts 46 and 41.The legs of the ladder 40 may be secured to the hoist legs 4| and 42 byany convenient means, such as bolts 48, and as seen best in Fig. 2, thehoist legs 4| and 42 with their associated ladder 4|! are adapted tonormally rest in a substantially horizontal position, so that thesupporting vehicle may be readily moved from place to place withoutinterference.

A shaft 49 is journaled in the hoist legs 4| and 42 and carries gearsand 5| adjacent its opposite ends outside of the legs 4| and 42 Whosefunction will be discussed later.

A pair of parallel horizontally-disposed slides 52 and 52a rest on thetable I4 and are slidable thereacross, being held in position by aplurality of upstanding guides 53 and 53a, 54 and 54a, respectively,said guides being provided with rollers 55 which bear upon the top faceof the slides 52 and 52a to hold them in position on the table l4. Theguides are preferably formed of pairs of opposed upstanding L-shapedsections, so as to prevent lateral movement of the slides. The slides 52and 52a are each provided with a notch 58 in their upper face adjacentone end thereof. The guides 53 and 5311. are provided with dogs 51carried by the channels 26 and 21, which are adapted to normally bearagainst the upper face of the slides 52 and 52a. and to engage thenotches 56 when the slides are in normal position as shown in Figs. 2and 5. Pivotally attached to the other end of slide 52 is a rack 60 anda similar rack 68a is pivotally connected to the rear end of slide 52a.The racks 68 and 60a are disposed, so that they rest on and engage gears50 and 5| respectively, and are held in engagement against theirrespective gears 58 and 5| by pairs of straps BI and Blu and 62 and 62apivotally mounted on the shaft 49 and extending therefrom on either sideof their respective racks. The outer ends of the straps 6| and Blu and62 and 62a are connected by short shafts upon which are rotatablymounted a pair of rollers 63 and 64 and 63a and 64a, respectively, whichrollers bear against the upper face of the racks 68 and 68a.

One end of the shaft 49, in the drawings the end which extends throughthe hoist leg 4|, is provided with a gear 65 adapted to mesh with asmaller gear 66 carried on a short shaft 61 which extends between leg 4|and a Wall 68. Shaft 61 extends through the wall 88 and carries a largegear 69 on its outer end, which in turn meshes with a small gear 18carried on a shaft journaled in wall 68 and the outside wall 1| of thegear box, the shaft of gear 18 carrying a handwheel 12 on its outer endoutside of the gear box, said gears forming a reduction gear train,whereby rotation of the handwheel 12 rotates the shaft 49 with itsassociated gears 50 and 5|.

A locking block 13 is mounted on the wall 14 of said gear box and isapertured and disposed so that it surrounds the shaft 61. The block 13is slit below the aperture which contains the shaft 61 and a bolt 15extends through the block 13 and wall 14 and is connected to aneccentric lever 16, so that movement of the lever causes the bolt 15 tocompress the two sections of the block 13 about the shaft 61 to lock itagainst rotation.

A shaft 80 is journaled between the anchor plates 26 and 21 and isprovided at each end with dogs 8| and Bio. which are pressed downwardlyby spring 82 surrounding the Shaft 88,

and are adapted to engage the notches 56 in the slides 52 and 52a whenthey travel to their lefthand position, as shown in dotted lines in Fig,5, and full lines in Fig. 6. The shaft 80 is provided with a handle 83by means of which the shaft 88 can be rotated against the action of thespring 82 to disengage the dogs 8| and Blu from their respective notchesin the slides 52 and 52a.

In the interest of safety and efficiency, We prefer to provide all ofthe gears with covers or housings as shown in the drawings, it beingthought unnecessary to specifically mention each covering by name andnumber.

In the normal position of our apparatus as shown in Figs. 1 and 2, thelegs 4| and 42 are substantially horizontal and the slides 52 and 52aare in their righthand position, the racks 68 and 68a being slightlyinclined and engaging the gears 50 and 5| as illustrated. To raise theladder .48 and position it for use, the locking block 13 is released andthe hand wheel 12 is rotated in a counter-clockwise direction, whichrotation by reason of the gear train connected thereto rotates the shaft48 and its gears 58 and 5| in a counter-clockwise manner. This rotationof the gears 58 and 5| which are in engagement with the racks 68 and 60acauses the racks to rotate clockwise about their pivotal mountings onslides 52 and 52a, and also causes said slides to move to the left inthe guides 53 and 54 until the arms 60 and 680. are in upright position(as seen in Fig. 5) and the notches 56 on the slides 52 and 52a havebeen engaged by the dogs 8| and Mo on the left side of the table 4. Thehandwheel 12 is then rotated in the opposite direction, in this caseclockwise, and since the slides 52 and 52a are locked by the dogs 8| andam against movement to the right, gears 50 and 5| are caused to travelup the racks 68 and 60a, causing both the legs 4| and 42 and the racksto rotate in a counter-clockwise direction to a position, such as shownin Fig. 6. It will be apparent that continued rotation of the handwheel12 will cause the gears 58 and 5| to travel out to the end of theirrespective racks 68 and 60a and the length of said racks is such thatwhen the gears reach the ends of their respective racks, the hoist legs4| and 42 are substantially vertical. It will be understood of coursethat the legs 4| and 42 can be stopped in any desired position betweenthe horizontal and the vertical, and while normally there is sufficientbraking effect by reason of the reduction gears, as a matter of cautionthe braking block 13 is. clamped around the shaft 61 by moving the lever16, so that further movement of the gears and shaft in either directionis prevented.

When the ladder has been erected, it can be positioned by rotating thetable M to any point desired by simply operating the handwheel 34through its gear train as previously described. It will be understood ofcourse, that if desired, the rotational position of the table M can beadjusted prior to the erection of the ladder.

When it is desired to lower the ladder, the brake block '13 is released,the handwheel 12 is rotated in a counter-clockwise direction until theladder has resumed its horizontal position, and the traveling racks arein a substantially vertical position as shown in dotted lines in Fig. 5.The handle 83 is then moved in a counterclockwise direction to disengagethe dogs 8| and 8| a from their respective notches in slides 52 and 52aand the handwheel 12 is rotated in a clockwise direction to cause theracks 6|) and 60a to travel along the gears 59 and Si until they are intheir retracted position, and the slides 52 and 52a have moved to theright end of their travel, at which point the dogs 57 and 51a engage thenotches 56 and prevent further movement of the slides and said racks.

While we have shown our preferred form of hoist as including means formoving the racks from retracted position to upright position, it is tobe understood that we also mean to include in our invention a hoist inwhich the racks are pivoted directly on the table with no means beingprovided for retracting them, in which case they would normally be in anupright position.

From the foregoing, it will be seen that we have provided a very simpleand durable hoisting device by means of which one man can raise, lower,and adjust a large ladder or other apparatus which otherwise would beimpossible for him to handle. While we have illustrated a preferredembodiment of our invention as applied to ladders, it is to beunderstood that our hoist can be used for many other purposes, and thatthe use of the word ladder herein is for convenient illustration and ismeant to include other apparatus with which our invention can besuccessfully associated.

We claim as our invention:

1. A ladder hoist of the character described which includes: a table;ladder-supporting means pivotally mounted on said table; gear meanscarried by said ladder-supporting means; a-horizontal slide mounted onsaid table; a rack pivotally mounted on said slide and engaging saidgear means; and means for rotating said gear means to thereby rotatesaid ladder-supporting means about its supporting point on said table.

2. A ladder hoist of the character described which includes: asubstantially horizontal table; a ladder support pivotally mounted atone end on said table; a transverse shaft journaled in said support andcarrying gear means; a horizontal slide mounted on said table; guides onsaid table for restricting the movement of said slide; a rack pivotallyconnected at one end to said slide; means carried by said support forholding said rack in engagement with said gear means; means for rotatingsaid gear means to cause it to travel along said rack; and means forlocking said slide in the position it assumes when said rack is in anupright position, whereby rotation of said gear means in one directionmoves said slide into locked position and raises said rack andsubsequent rotation of said gear means in the opposite direction raisessaid ladder support.

3. A ladder hoist of the character described which includes: asubstantially horizontal table; a pair of ladder supporting legspivotally mounted at one end on said table; a pair of horizontal slideson said table with guides for restricting their movement; a rackpivotally mounted on each of said slides; a transverse shaft journaledin said legs carrying a gear adjacent each end thereof adapted to engagesaid racks; means for holding said racks in engagement with theirrespective gears; a reduction gear train associated with said gearshaft; and means for locking said slides in the position they assumewhen said racks reach an upright position by reason of rotation of saidgears in one direction, whereby rotation thereof in the oppositedirection causes them to ride up said racks thereby raising said legsabout their pivotal mountings.

4. A ladder hoist as defined in claim 3 in which one of the gears ofsaid train is mounted on a shaft which has an apertured block associatedtherewith adapted to lock said shaft and thereby said legs in anydesired position,

5. A ladder hoist as defined in claim 3 in which said slide lockingmeans comprises spring pressed dogs carried on said table.

6., A ladder hoist as defined in claim 3 in which the means for holdingthe rack in engagement with the gear comprises strap means mounted onthe gear shaft and extending outwardly beyond said rack, and providedwith a pair of rollers which ride on the upper face of said rack.

7. A ladder hoist of the character described which includes: a table;ladder-supporting means pivotally mounted on said table; gear meanscarried by said ladder-supportng means; a horizontal slide mounted onsaid table; guides on said table for restricting the movement of saidslide; a rack pivotally mounted on said slide and engaging said gearmeans; means for rotating said gear means; and means for locking saidslide in the position it assumes when said rack is in an uprightposition, whereby rotation of said gear means in one direction movessaid slide into locked position and raises said rack and subsequentrotation of said gear means in the opposite direction raises said laddersupport.

8. A ladder hoist of the character described which includes: asubstantially horizontal table; a ladder-support pivotally mounted atone end on said table; a transverse shaft journaled in said support andcarrying gear means; a horizontal slide mounted on said table; a rackpivotally connected at one end to said slide; means carried by saidsupport for holding said rack in engagement with said gear means; andmeans for rotating said gear means to cause it to travel along said rackand thereby rotate said ladder support about its pivotal mounting.

9. A ladder hoist of the character described which includes: a table;ladder-supporting means pivotally mounted on said table; gear meanscarried by said ladder-supporting means; a rack pivotally mounted onsaid table and slidable thereon, and engaging said gear means; means forrotating said gear means to thereby rotate said ladder-supporting meansabout its supporting point on said table; and locking means cooperatingwith said rack, whereby rotation of said gear means while said lockingmeans is disengaged causes rotation of said rack, and rotation of saidgear means in the opposite direction when said locking means is engagedcauses rotation of said ladder-supporting means.

10. A ladder hoist of the character described which includes: asubstantially horizontal table; a ladder support pivotally mounted atone end on said table; a transverse shaft journaled in said support andcarrying gear means; a rack pivotally connected at one end to said tableand slidable thereon; means carried by said support for holding saidrack. in engagement with said gear means; means for rotating said gearmeans to cause it to travel along said rack and thereby rotate saidladder support about its pivotal mounting; and locking means cooperatingwith said rack, whereby rotation of said gear means while said lockingmeans is disengaged causes rotation of said rack, and rotation of saidgear means in the opposite direction when said looking means is engagedcauses rotation of said ladder-supporting means.

WILLIAM G. KUEHN. MONTE E. HOVER.

